diff options
author | Al Viro <viro@zeniv.linux.org.uk> | 2023-10-31 07:23:35 +0300 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2023-11-25 10:33:42 +0300 |
commit | b06c684d3984ef64e792ec3e89889c96cab97b5e (patch) | |
tree | c1f0d16c9ac339a158c33fcb7240250d5019abf8 /fs | |
parent | ee0c82503dcd0d14cc1ad53da18d32a04f612c4c (diff) | |
download | linux-b06c684d3984ef64e792ec3e89889c96cab97b5e.tar.xz |
dentry_kill(): don't bother with retain_dentry() on slow path
We have already checked it and dentry used to look not worthy
of keeping. The only hard obstacle to evicting dentry is
non-zero refcount; everything else is advisory - e.g. memory
pressure could evict any dentry found with refcount zero.
On the slow path in dentry_kill() we had dropped and regained
->d_lock; we must recheck the refcount, but everything else
is not worth bothering with.
Note that filesystem can not count upon ->d_delete() being
called for dentry - not even once. Again, memory pressure
(as well as d_prune_aliases(), or attempted rmdir() of ancestor,
or...) will not call ->d_delete() at all.
So from the correctness point of view we are fine doing the
check only once. And it makes things simpler down the road.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/dcache.c | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index b527db8e5901..80992e49561c 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -739,14 +739,10 @@ slow_positive: spin_lock(&dentry->d_lock); parent = lock_parent(dentry); got_locks: - if (unlikely(dentry->d_lockref.count != 1)) { - dentry->d_lockref.count--; - } else if (likely(!retain_dentry(dentry))) { - dentry->d_lockref.count--; + dentry->d_lockref.count--; + if (likely(dentry->d_lockref.count == 0)) { __dentry_kill(dentry); return parent; - } else { - dentry->d_lockref.count--; } /* we are keeping it, after all */ if (inode) |